1. Field of the Invention
The present invention relates to a network operations management method and apparatus which operates each of a plurality of physical servers logically as at least one virtual server and dynamically changes virtual servers to be allocated to the respective physical servers by moving the virtual server between the physical servers.
2. Description of the Related Art
A virtualization technique for effectively utilizing computer resources (physical resources) of a plurality of physical servers by operating each of the physical servers logically as at least one server (virtual server) is known.
Non-patent documents 1 and 2 disclose techniques for improving the efficiency of the operations of network devices and servers by using such a virtualization technique. The VMware ESX disclosed in Non-patent document 1 is a technique for constructing a plurality of virtual servers by dividing physical resources such as a processor, memory, storage, and network bandwidth, etc., of a physical server. According to this VMware ESX, a plurality of virtual servers can operate concurrently by sharing physical resources on the same physical server.
Patent document 1 and Non-patent documents 3 and 4 disclose techniques for further improving the efficiency of operations by (1) assigning physical resources to virtual servers and (2) dynamically changing the physical servers which operate the virtual servers according to the use of the virtual servers by applying the virtualization technique.
FIG. 9 and FIG. 10 are block diagrams schematically showing an operations optimization method using a conventional virtualization technique. In the data center DC, two network segments NS1 (192.168.1.0/24) and NS2 (192.168.2.0/24) connected to a network via a router R1 and switches SW1, SW2, and SW3 exist. To the first network segment NS1, four physical servers PS1, PS2, PS3, and PS4 are connected, and similarly, to the second network segment NS2, four physical servers PS5, PS6, PS7, and PS8 are connected.
In the conventional technique, a plurality of physical servers are bundled in logical groups, and in each logical group, (1) physical resources are assigned to virtual servers and (2) physical servers which operate virtual servers are dynamically changed. Here, the logical group is referred to as a resource pool RP. Generally, a virtual server must continuously use the same address even after the physical server on which the virtual server itself operates is dynamically changed, so that the physical servers connected to the same network segment are bundled in the same resource pool RP. In the example of FIG. 9 and FIG. 10, the physical server group connected to the network segment NS1 is bundled in the resource pool RP1, and the physical server group connected to the network segment NS2 is bundled in the resource pool RP2.
In each of the physical servers PS1 to PS8, the VMware ESX is installed as a virtualization platform, and the physical resources (processors, memories, storages, and network resources, etc.) of the physical servers are virtually divided and assigned to the respective virtual servers.
In a time period with comparatively high utilization of virtual servers such as during daytime or working hours, all physical servers PS1 to PS8 are running as shown in FIG. 9, and various application Apps are executed in a dispersed manner on the operating systems of the plurality of virtual servers which operate on the physical servers PS. On the other hand, during nighttime or outside of working hours in which the access number is less, as shown in FIG. 10, in the first resource pool RP1, three virtual servers which had operated on the two physical servers PS3 and PS4 are consolidated into two physical servers PS1 and PS2, and two physical servers PS3 and PS4 are turned into a turned-off state or a hibernation state with less power consumption.
Similarly, in the second resource pool RP2, three virtual servers which had operated on two physical servers PS7 and PS8 are consolidated into two physical servers PS5 and PS6, and two physical servers PS7 and PS8 are turned into a turned-off state or a hibernation state.    Patent document 1: Japanese Published Unexamined Patent Application No. 2007-310791    Non-patent document 1: VMware: http://www.vmware.com/    Non-patent document 2: Xen: http://www.xen.org/    Non-patent document 3: “Power saving technology with visualization”; IEICE (The Institute of Electronics, Information and Communication Engineers) technical report. Computer systems, vol. 106, no. 436, CPSY2006-44, pp. 37-42, December 2006.    Non-Patent document 4: VMware Distributed Power Management (DPM)
In the above-described conventional technique, a virtual server cannot be moved between physical servers in different network segments (that is, in different resource pools), so that it is difficult to sufficiently improve the efficiency.
As in the conventional technique shown in FIG. 10, when virtual servers are allocated to the respective physical servers, the physical servers PS3, PS4, PS7, and PS8 can be shutdown, so that power-saving can be realized to some degree. However, the total power consumption of the data center DC greatly depends on the power consumption of air-conditioning equipment, lighting facilities, and switches SW for switching the lines of the physical servers as well as the power consumption of the physical servers. Therefore, as shown in FIG. 11, when the resource pools RP1 and RP2 are installed in different rooms, if all virtual servers can be allocated to the physical servers installed in one room 1, all of the physical servers PS and switches SW thereof allocated in the other room 2 can be shutdown, and the air-conditioning equipment and lighting facilities in the room 2 can also be stopped.
However, with the above-described conventional technique, grouping of the physical servers bundled in the respective resource pools cannot be dynamically changed, so that it is difficult to further save power by reallocating the virtual servers between physical servers beyond the network segments as described in FIG. 11.